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WA. UBC Section 1630.9 deals with Drift and Drift Calculation requirements. Section 1630.9.1 outlines the procedure for determination of Delta_S i.e., structural deformation due to seismic effects, whereas Section 1630.9.2 is related to the determination of Maximum Inelastic Response Displacement (Delta_M). Story Drift Limitations are given in UBC Section 1630.10. Regards.

Can shear failure of structural walls trigger collapse of reinforced concrete building if the building satisfies drift limits and its frame can independently take 50 percent of seismic force in both directions.

It is 25% of base shear. Yes, something like that.

Yes there is; read the section 1630.9.2 of the UBC 97.

Yes, beam moments are separate. Strips show moments only for slab areas not for line elements.

1. According to ACI Concrete Terminology 2013, Mass Concrete is "any volume of concrete in which a combination of dimensions of the member being cast, the boundary conditions can lead to undesirable thermal stresses, cracking, deleterious chemical reactions, or reduction in the long-term strength as a result of elevated concrete temperature due to heat from hydration." Now, first of all it is necessary to check whether your concrete really comes under the definition of Mass Concrete or not. ACI 207.1R-05 does provide basic information & general guidance about mass concrete, but it does not specify any minimum dimensions of concrete to qualify as 'Mass Concrete'. Following links however suggest some critical dimensions of concrete to consider it 'mass concrete', as well as useful information regarding placement of mass concrete and recommended practice for effective control of heat of hydration & thermal cracking in mass concrete. a. https://www.concrete.org/tools/frequentlyaskedquestions.aspx?faqid=650 b. http://people.wallawalla.edu/~larry.aamodt/engr325/concrete_heating.pdf c. http://www.nrmca.org/aboutconcrete/cips/42p.pdf d. https://www.structurepoint.org/publication/pdf/pdh-Mass-Concrete-Structures.pdf e. ACI 301-05, Section 8 Mass Concrete (Includes required concrete placement temperatures, among others) f. http://people.ce.gatech.edu/~kk92/massconcrete.pdf g. http://www.agcia.org/documents/Mass Concrete Thermal Control.pdf In case your concrete tunnel lining actually falls within definition of Mass Concrete, you will need to adopt suitable measures (including installation of thermocouples, as advised above by Umar) to keep the concrete temperatures within limits recommended for mass concrete. 2. Alternately, you may ask your consultant to provide you the calculations to prove that concreting you are doing is mass concrete, and also to provide you the reference that requires waiting for 72 hours, to start the next pour. 3. You may possibly do such calculations yourself too, provided you have relevant temperature values and other required information. Guidance is available in following document:- http://www.oea.org.lb/Library/Files/Arabic/Downloads/Reports/ندوات ومؤتمرات/Presentation Mass Concrete OEA dec 20.pdf I don't have some reference now. However, if the tunnel lining concrete does not qualify for mass concrete, in the light of documents referred earlier, or (as already said earlier) the concrete reinforcement design & placement is adequate to counter both the applicable loads as well as thermal cracking, 72 hour restriction might not be applicable. In such a case, you can start next pour earlier. Regards.

It is explained in the manual that you can download from http://www.sepakistan.com/topic/1322-how-to-design-t-or-l-beams-in-etabs/ I have also attached the snapshot from the manual that explains how Etabs checks beam column capacities.